Projector

ABSTRACT

This invention provides a technique of reducing temperature rise due to heat generation of polarization control elements. A projector includes: an illumination optical system; an electro-optical device for modulating light from the illumination optical system in response to image information; a projection optical system for projecting modulated light obtained with the electro-optical device; and a base frame, formed using material including metal material, for mounting a plurality of optical components arranged on an optical path from the illumination optical system to the projection optical system. At least one of the plurality of optical components is a polarization control component that includes: a polarization control element including organic material for the controlling polarization state of light exiting from the polarization control element; and a light-transmissive member having a thermal conductivity of at least about 0.8 W/(m·K), to which the polarization control element is stuck. The light-transmissive member and the base frame are thermally coupled.

TECHNICAL FIELD

[0001] This invention relates to a projector for projecting anddisplaying images.

BACKGROUND ART

[0002] Projectors display images by modulating light from anillumination optical system in response to image information (imagesignal) by means of a liquid crystal panel, and projecting the modulatedlight onto a screen.

[0003] A liquid crystal light valve is typically composed of a liquidcrystal panel, and a polarizing plate provided to the light incidentside and/or light exiting side thereof The polarizing plate allowstransmission of only the component of light in the direction of thepolarization axis, and blocks other components of light. Where apolarizing plate includes organic material, the polarizing plate absorbslight other than the light component in the direction of thepolarization axis, and thus generates heat. If due to this heatgeneration the temperature of the polarizing plate rises, distortion anddeterioration of the polarizing plate may occur, and opticalcharacteristics may drop. Specifically, the polarizing plate allowstransmission of the light component that should not pass through, andblocks the light component that should not be blocked. For this reason,in the past, a cooling fan was used to actively cool the liquid crystallight valve including the polarizing plate.

[0004] However, when miniaturizing a projector, it may be difficult toinstall a cooling fan, or it will be necessary to miniaturize thecooling fan. In such cases, there has been the problem that thepolarizing plate cannot be cooled adequately, and the temperature riseof the polarizing plate becomes relatively large.

[0005] This problem is common to any optical elements including organicmaterial for controlling the polarization state of light exiting fromthe optical elements (hereinafter also termed “polarization controlelements”).

DISCLOSURE OF THE INVENTION

[0006] The object of the present invention is thus to solve thedrawbacks of the prior art discussed above and to provide, in aprojector, a technique of reducing temperature rise due to heatgeneration of polarization control elements.

[0007] At least part of the above and the other related objects isattained by an apparatus of the present invention, which is a projectorthat includes: an illumination optical system; an electro-optical devicefor modulating light from the illumination optical system in response toimage information; a projection optical system for projecting modulatedlight obtained with the electro-optical device; and a base frame, formedusing material including metal material, for mounting a plurality ofoptical components arranged on an optical path from the illuminationoptical system to the projection optical system. At least one of theplurality of optical components is a polarization control component thatincludes: a polarization control element including organic material forcontrolling the polarization state of light exiting from thepolarization control element; and a light-transmissive member having athermal conductivity of at least about 0.8 W/(m·K), to which thepolarization control element is stuck. The light-transmissive member andthe base frame are thermally coupled.

[0008] In the apparatus of the present invention, the polarizationcontrol element is stuck to the light-transmissive member of relativelyhigh thermal conductivity. Further, the light-transmissive member isthermally coupled to the base frame including a metal material ofrelatively high thermal conductivity. Therefore, heat generated by thepolarization control elements can be transferred to thelight-transmissive member and base frame, and as a result, it ispossible to reduce the temperature rise due to heat generation ofpolarization control elements.

[0009] Here, a “thermally coupled” state means a state in which heat isrelatively easily transferred. Also, the state of the light-transmissivemember and base frame being thermally coupled includes a state in whichthe light-transmissive member and base frame are in mutual contact, or astate in which a member of relatively high thermal conductivitycontacting both the light-transmissive member and base frame isinterposed.

[0010] In the above apparatus, it is preferable that thelight-transmissive member has a thermal conductivity of at least about5.0 W/(m·K). By using this light-transmissive member, the advantage ofthe present invention becomes prominent.

[0011] In the above apparatus, it is preferable that the base frame ismade of metal. By so doing, the thermal conductivity of the base framecan be made relatively high, and so it becomes possible to reduce thetemperature rise due to the heat generation of polarization controlelement.

[0012] In the above apparatus, the polarization control component may beheld by a metal holder that makes contact with the light-transmissivemember, and the light-transmissive member and the base frame may bethermally coupled via at least the holder. Even if a metal holder ofrelatively high thermal conductivity is interposed between thelight-transmissive member and the base frame, heat generated by thepolarization control element can be transferred to the base frame, andtemperature rise due to heat generation of the polarization controlelement can be reduced. Also, a plurality of members of relatively highthermal conductivity can be interposed between the base frame and thelight-transmissive member which is stuck to the polarization controlelement.

[0013] Here, the holder may be fixed to the base frame via an adhesivesheet or adhesive, or by metal welding. Also the light-transmissivemember may be fixed to the holder via an adhesive sheet or adhesive. Itis preferable that the adhesive sheet or adhesive has relatively highthermal conductivity. In this way, in the case that an adhesive oradhesive sheet of relatively small thickness is interposed between theholder and the base frame, the holder and the base frame are notcontacting directly, but are close, so that heat generated by thepolarization control element can be transmitted to the base frame. Thecase where an adhesive sheet or adhesive is interposed between thelight-transmissive member and the holder is similar. If the holder andbase frame are joined by metal welding, heat generated by thepolarization control element can be transferred efficiently to the baseframe.

[0014] That is, the aforementioned “thermally coupled” state will be astate relatively easy heat transfer, and includes a state in which anadhesive or adhesive sheet of relatively small thickness is interposedbetween the light-transmissive member and base frame.

[0015] In the above apparatus, the holder may include: a fixing sectionfixed to the base frame; and an attaching section for attaching thelight-transmissive member to the fixing section. Here, the fixingsection may be fixed to the base frame via an adhesive sheet oradhesive, or by metal welding. Also, the light-transmissive member maybe stuck to the fixing section and/or the attaching section via anadhesive sheet or adhesive.

[0016] It is preferable that the above apparatus further includes ametal chassis for housing all optical components arranged on the opticalpath from the illumination optical system to the projection opticalsystem. In this case, it is preferable that the base frame and thechassis are thermally coupled. This arrangement allows heat generated bythe polarization control element to be transferred from the base frameto the chassis, so temperature rise due to heat generation ofpolarization control element can be reduced.

[0017] In the above apparatus, it is preferable that the illuminationoptical system includes a light source device, wherein the light sourcedevice and the base frame are thermally insulated. The light sourcedevice has relatively large heat emission. Accordingly, by thermallyinsulating the light source device and the base frame, temperature riseof the base frame due to heat emission by the light source device can bereduced, and as a result heat generated by the polarization controlelement can be efficiently transferred to the base frame.

[0018] Here, a “thermally insulated” state means a state in which heatis relatively difficult to transfer, and includes a state in which aninsulating member is interposed between the light source device and thebase frame.

[0019] The above apparatus may further include a cooling fin, providedon the outside face of the base frame. In this arrangement, the baseframe can be cooled, so the heat generated by the polarization controlelement can be efficiently transferred to the base frame.

[0020] In the above apparatus, it is preferable that a film for raisingthe radiation rate is formed on the outside face of the base frame. Inthis arrangement, the base frame temperature can be made relatively low,so that temperature rise due to heat generation of polarization controlelement can be further reduced.

[0021] It is also preferable that a film for raising the radiation rateis formed on the outside face of the chassis. In this arrangement, theheat of the chassis can be efficiently radiated to the outside, so thatit becomes possible to further reduce temperature rise due to heatgeneration of polarization control element.

[0022] In the above apparatus, the polarization control element may be aliquid crystal panel as the electro-optical device, a polarizing plate,or a retardation plate.

[0023] In the above apparatus, the light-transmissive member may be alens.

[0024] Alternatively, the polarization control component may furtherinclude a lens, the lens being provided on the plate shapedlight-transmissive member. By so doing, compared to the case where thelight-transmissive member is a lens, a polarization control componenthaving a lens function can be fabricated relatively easily.

[0025] In the above apparatus the lens may be formed of plastic. In thiscase, lens faces can be fabricated relatively easily.

[0026] In the above apparatus, the light-transmissive member may be asapphire member or a rock crystal member. These members have arelatively high thermal conductivity of at least about 5.0 W/(m·K), sothat temperature rise due to heat generation of polarization controlelement can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a simplified schematic diagram showing an example of aprojector;

[0028]FIG. 2 is an illustrative diagram showing an enlarged view of theillumination optical system 100 of FIG. 1;

[0029] FIGS. 3(A) and 3(B) are illustrative diagrams showing an enlargedview of the first polarizing element array 160A of FIG. 2;

[0030]FIG. 4 is an explanatory diagram showing an enlarged view ofliquid crystal light valves 300R, 300G, 300B and the cross dichroicprism 360 of FIG. 1;

[0031]FIG. 5 is a schematic cross section of liquid crystal panel 310G;

[0032]FIG. 6 is a schematic cross sectional view showing the typicalbase frame 600 and chassis 800 of projector 1000;

[0033]FIG. 7 is an explanatory diagram of the first holder 710 thatholds the first polarization control component consisting ofpolarization generating optical system 160 only;

[0034]FIG. 8 is an explanatory diagram of the second holder 720 thatholds the second polarization control component, consisting of the firstpolarizing plate 320Gi and the light-transmissive substrate 321;

[0035]FIG. 9 is an explanatory diagram of the third holder 730 thatholds the third polarization control component, consisting of the liquidcrystal panel 310G and the pair of light-transmissive substrates 311,312;

[0036]FIG. 10 is an explanatory diagram showing a field lens 234′, withthe first polarizing plate 320Gi stuck to it;

[0037]FIG. 11 is an explanatory diagram showing a holder 750 that holdsa polarization control component consisting of the first polarizingplate 320Gi and field lens 234′ shown in FIG. 10;

[0038]FIG. 12 is an explanatory diagram showing a first modification ofa field lens with a first polarizing plate 320Gi stuck to it;

[0039]FIG. 13 is an explanatory diagram showing a second modification ofa field lens with a first polarizing plate 320Gi stuck to it;

[0040]FIG. 14 is an explanatory diagram showing a holder 730A that holdsthe third polarization control component consisting of liquid crystalpanel 310G and a pair of light-transmissive substrates 311, 312;

[0041]FIG. 15 is an explanatory diagram showing a chassis 800A in theFourth Embodiment;

[0042] FIGS. 16(A) and 16(B) are explanatory diagrams showing a holder701 that holds a plurality of optical components included in theillumination optical system 100;

[0043]FIG. 17 is a simplified perspective diagram showing a base frame600B on which optical components of the projector will be mounted in theSixth Embodiment;

[0044]FIG. 18 is a simplified perspective diagram showing the base frame600B on which the optical components of projector have been mounted;

[0045]FIG. 19 is an explanatory diagram showing a third holder 730B thatholds a third polarization control component, consisting of a liquidcrystal panel 310G and a pair of light-transmissive substrates 311, 312in the Sixth Embodiment;

[0046]FIG. 20 is a perspective diagram showing the situation in which abase frame cover 680B is attached to the base frame 600B of FIG. 18;

[0047]FIG. 21 is an explanatory diagram showing the outside of chassis800B;

[0048]FIG. 22 is an explanatory diagram showing the condition of theinterior of the chassis 800B shown in FIG. 21;

[0049]FIG. 23 is an explanatory diagram showing the situation around thefirst cooling fan 410B shown in FIG. 22;

[0050]FIG. 24 is an explanatory diagram showing the outside face of thebottom portion of base frame 600B;

[0051]FIG. 25 is an explanatory diagram showing the conditions insidethe chassis 800B in the Seventh Embodiment; and

[0052]FIG. 26 is a schematic cross sectional view when the proximity ofheat pipe 400 shown in FIG. 25 is cut in a plane parallel to the xzplane.

BEST MODE FOR CARRYING OUT THE INVENTION

[0053] A. First Embodiment:

[0054] One mode of carrying out the present invention is discussed belowas a preferred embodiment. FIG. 1 is a simplified schematic diagramshowing an example of a projector. Projector 1000 comprises anillumination optical system 100, a color separation optical system 200,a relay optical system 220, three liquid crystal light valves 300R,300G, 300B, a cross dichroic prism 360, and a projection optical system380.

[0055] Light output from the illumination optical system 100 isseparated by the color separation optical system 200 into colored lightof the three colors of red (R), green (G) and blue (B). The separatedcolored lights are modulated by liquid crystal light valves 300R, 300G,300B in response to image information. Modulated lights are combined bythe cross dichroic prism 360, and the composite light is projected ontoa screen SC by the projection optical system 380. By means of this animage is displayed on the screen SC.

[0056]FIG. 2 is an illustrative diagram showing an enlarged view of theillumination optical system 100 of FIG. 1. The illumination opticalsystem 100 comprises a light source device 120, first and second lensarrays 140, 150, a polarization generating optical system 160, and asuperimposing lens 170. The optical components are aligned along to asystem optical axis 100 ax. Here, the system optical axis 100 ax is thecenter axis of the beam of light output by light source device 120. InFIG. 2, a lighted area LA illuminated by the illumination optical system100 corresponds to the liquid crystal light valves 300R, 300G, 300B ofFIG. 1.

[0057] The light source device 120 comprises a lamp 122, a reflector 124having a concave face of spheroid, and a parallelizing lens 126. Thelamp 122 is situated in proximity to a first focal point of the spheroidof the reflector 124. Light output by the lamp 122 is reflected by thereflector 124, and the reflected light is converged while advancingtowards the second focal point of reflector 124. The parallelizing lens126 converts incident converged light to light substantially parallel tothe system optical axis 100 ax.

[0058] The first and second lens arrays 140, 150 have a plurality ofsmall lenses 142, 152 arrayed in matrix configuration. The first lensarray 140 has the function of splitting the substantially parallel lightbundle output from the light source device 120 into a plurality ofpartial light bundles for output. The second lens array 150 has thefunction of aligning the partial light bundles output from the firstlens array 140 so that their center axes are substantially parallel tothe system optical axis 100 ax. The second lens array 150, together withthe superimposing lens 170, has the function of forming the images ofsmall lenses 142 of first lens array 140 into an image on the lightedarea LA.

[0059] The small lenses 142, 152 are plano-convex decentered lenseswhose external shape, viewed from the x direction, is substantiallysimilar to that of the lighted area LA (liquid crystal light valves). Asshown in FIG. 2, decenterd lenses having different manners ofeccentricity are used for the first small lens 142 and second small lens152. Specifically, the outermost peripheral small lens 142 of the firstlens array 140 is decentered such that the principal ray of a splitpartial light bundle proceeds on the diagonal with respect to the systemoptical axis 100 ax. The outermost peripheral small lens 152 of thesecond lens array 150 is decentered such that the principal ray of asplit partial light bundle incident on the diagonal with respect to thesystem optical axis 100 ax becomes substantially parallel to the systemoptical axis 100 ax.

[0060] Partial light bundles output by the small lenses 142 of the firstlens array 140 are, as shown in FIG. 2, via the small lenses of thesecond lens array 150, converged at a location in proximity thereto,namely, within the polarization generating optical system 160.

[0061] The polarization generating optical system 160 comprises twopolarizing element arrays 160A, 160B that have been integrated. Thepolarizing element arrays 160A, 160B are arranged so as to besymmetrical with respect to the system optical axis 100 ax.

[0062] FIGS. 3(A) and 3(B) are illustrative diagrams showing an enlargedview of the first polarizing element array 160A of FIG. 2. FIG. 3(A) isa perspective view of the first polarizing element array 160A, and FIG.3(B) is a plan view thereof viewed from the +z direction. The firstpolarizing element array 160A comprises a light blocking plate 162, apolarization beam splitter array 164, and a plurality of λ/2 retardationplates 166 selectively arranged at the exiting light face of thepolarization beam splitter array 164. The second polarizing elementarray 160B is of similar design.

[0063] As shown in FIGS. 3(A) and (B), the polarization beam splitterarray 164 is composed of a plurality of columnar light-transmissivemembers 164 c of practically parallelogrammatic cross section, stucktogether. Polarization separating films 164 a and reflective films 164 bare formed alternately at the interfaces of light-transmissive members164 c.

[0064] The light blocking plate 162 is composed of open faces 162 a andlight blocking faces 162 b arranged in striped configuration. The openfaces 162 a and the light blocking faces 162 b are provided inassociation with the polarization separating films 164 a and thereflective films 164 b respectively. In this way, a partial light bundleexiting from the first lens array 140 (FIG. 2) enters only thepolarization separating films 164 a of the polarization beam splitterarray 164 via the open faces 162 a, and does not enter the reflectivefilms 164 b.

[0065] As indicated by the solid line in FIG. 3(B), the principal ray(center axis) of a partial light bundle exiting from the first lensarray 140 (FIG. 2) enters the open face 162 a of the light blockingplate 162 in a direction substantially parallel to the system opticalaxis 100 ax. The partial light bundle passing through the open face 162a is separated into an s-polarized partial light bundle and ap-polarized partial light bundle by the polarization separating films164 a. The p-polarized partial light bundle transmits the polarizationseparating films 164 a and is output from the polarization beam splitterarray 164. On the other hand, the s-polarized partial light bundle isreflected by the polarization separating films 164 a, again reflectedoff the reflecting film 164 b, and then output from the polarizationbeam splitter array 164. At the light exiting face of the polarizationbeam splitter array 164, the p-polarized partial light bundle ands-polarized partial light bundle are substantially parallel to eachother.

[0066] The λ/2 retardation plates 166 are formed on the light exitingface of the polarization beam splitter array 164, exclusively in thelight exiting face of p-polarized light bundles having transmittedthrough polarization separating films 164 a. The λ/2 retardation plates166 have the function of converting linearly polarized incident lightinto linearly polarized light having an orthogonal polarizationdirection. Thus, a p-polarized partial light bundle is output afterbeing converted into an s-polarized partial light bundle by the λ/2retardation plates 166. Thus, a non-polarized partial light bundle (s+p)entering polarizing element array 160A is output after being convertedto s-polarized partial light bundles.

[0067] As noted, the plurality of partial light bundles exiting thefirst lens array 140 are separated by the polarization generatingoptical system 160 into two partial light bundles for each partial lightbundle, and converted into substantially a single kind of linearlypolarized light having matched polarization direction. The plurality ofpartial light bundles having matched polarization direction aresuperimposed on lighted area LA by the superimposing lens 170 of FIG. 2.The light falling on lighted area LA has a substantially uniformintensity distribution.

[0068] In this way, illumination optical system 100 (FIG. 1) outputsillumination light of matched polarization direction (s-polarizedlight), and illuminates liquid crystal light valves 300R, 300G, 300B viathe color separation optical system 200 and the relay optical system220.

[0069] The color separation optical system 200 (FIG. 1) comprises twodichroic mirrors 202, 204 and a reflecting mirror 208. This system 200has the function of separating light output from the illuminationoptical system 100 into colored light of the three colors red (R), green(G) and blue (B). The first dichroic mirror 202 reflects red coloredlight R in the light output from the illumination optical system 100,and allows transmission of blue colored light B and green colored lightG. The red colored light R reflected by the first dichroic mirror 202 isreflected by the reflecting mirror 208 and then passes through a fieldlens 232 to enter the liquid crystal light valve 300R for red coloredlight. The field lens 232 has the function of converting each partiallight bundle exiting from the illumination optical system 100 into alight bundle substantially parallel to the system optical axis 100 ax.The field lenses 234, 230 provided to the other liquid crystal lightvalves 300G, 300B also function similarly.

[0070] Blue colored light B and green colored light G transmittedthrough the first dichroic mirror 202 are separated by the seconddichroic mirror 204. Green colored light G is reflected by the seconddichroic mirror 204 and then passes through the field lens 234 to enterthe liquid crystal light valve 300G for green colored light. Bluecolored light B, on the other hand, transmits through the seconddichroic mirror 204 and then enters the relay optical system 220.

[0071] Blue colored light B entering the relay optical system 220 passesthrough an incident side lens 222, first reflecting mirror 224, relaylens 226, second reflecting mirror 228, and exiting side lens (fieldlens) 230 provided to the relay optical system 220, and enters theliquid crystal light valve 300B for blue colored light. The reason foremploying a relay optical system 220 on the optical path of blue coloredlight B is that the optical path length of the blue colored light B islonger than the optical path lengths of the other colored lights R andG. The use of a relay optical system 220 allows blue colored incidentlight B on the incident side lens 222 to be transmitted as-is to theexiting side lens 230.

[0072] The three liquid crystal light valves 300R, 300G, 300B modulatethe three incident colored lights according to given image information(image signal) and generate three modulated lights, respectively. Crossdichroic prism 360 combines the three modulated lights output from thethree liquid crystal light valves.

[0073]FIG. 4 is an explanatory diagram showing an enlarged view ofliquid crystal light valves 300R, 300G, 300B and the cross dichroicprism 360 of FIG. 1. While the following description emphasizes thesecond liquid crystal light valve 300G, the other liquid crystal lightvalves 300R, 300G are also similar.

[0074] The second liquid crystal light valve 300G comprises a liquidcrystal panel 310G, and two polarizing plates 320Gi, 320Go provided atthe light incident side and light exiting side thereof. To the lightincident face and light exiting face of the liquid crystal panel 310Gare stuck light-transmissive substrates 311, 312. To the firstpolarizing plate 320Gi provided at the light incident side is stuck alight-transmissive substrate 321. To the second polarizing plate 320Goprovided at the light exiting side is stuck the cross dichroic prism360.

[0075]FIG. 5 is a schematic cross section of the liquid crystal panel310G. As shown in the drawing, the liquid crystal panel 310G comprises apair of glass substrates 301, 302, a liquid crystal layer 304 sandwichedbetween the pair of glass substrates 301, 302, and a sealing member 304sthat prevents leaking out of liquid crystal. On the liquid crystal layer304 side of the first glass substrate 301 there is formed a transparentcommon electrode 301a. On the liquid crystal layer 304 side of thesecond glass substrate 302 there are thin film transistors (not shown)and transparent pixel electrodes 302 a, formed per pixel in matrixconfiguration. As explained in FIG. 4, the light incident face of liquidcrystal panel 310G is stuck to the first light-transmissive substrate311, and the light exiting face is stuck to the secondlight-transmissive substrate 312.

[0076] Colored light G entering the second liquid crystal light valve300G of FIG. 4 is output by an illumination optical system 100 (FIG. 1)comprising a polarization generating optical system 160, and thereforeincludes substantially one kind of linearly polarized light. The firstpolarizing plate 320Gi situated at the light incident side of the secondliquid crystal light valve 300G is arranged such that the polarizationaxis is the same as the polarization direction of incident linearlypolarized light. Accordingly, substantially all of the colored light Gentering the first polarizing plate 320Gi transmits as-is through thefirst polarizing plate 320Gi. Polarized light output from the firstpolarizing plate 320Gi is modulated by the liquid crystal panel 310G. Ofthe light modulated by the liquid crystal panel 310G, the secondpolarizing plate 320Go only outputs the light component whosepolarization direction is the same as the polarization axis. Modulatedlight output from the second polarizing plate 320Go (linearly polarizedlight) enters the cross dichroic prism 360.

[0077] The liquid crystal panels 310R, 310G, 310B included in the liquidcrystal light valves 300R, 300G, 300B correspond to the electro-opticaldevices of the present invention.

[0078] The cross dichroic prism 360 (FIG. 4) combines the colored lightof three colors (modulated light) modulated by liquid crystal lightvalves 300R, 300G, 300B, to generate composite light representing acolor image. The cross dichroic prism 360 is divided by interfaces ofroughly X-shaped configuration into four right angle prisms 360 a-360 das light-transmissive members. A red colored light-reflective film 361and a blue colored light-reflective film 362 are formed at theinterfaces of the X shape. Reflective films 361, 362 are formed ofdielectric multilayer films.

[0079] Modulated colored light R (linearly polarized light) output fromthe first liquid crystal light valve 300R is reflected by the redcolored light-reflective film 361 of the cross dichroic prism 360, andmodulated colored light B (linearly polarized light) output from thethird liquid crystal light valve 300B is reflected by the blue coloredlight-reflective film 362. Meanwhile, modulated colored light G(linearly polarized light) output from the second liquid crystal lightvalve 300G transmits through the two reflective films 361, 362 of thecross dichroic prism 360. By means of the red colored light-reflectivefilm 361 and the blue colored light-reflective film 362, the threecolored lights are combined to generate composite light representing acolor image. For convenience in illustration, in FIG. 4 the locations atwhich red colored light R and blue colored light B are reflected areshown at locations apart from the two reflective films 361, 362.

[0080] The projection optical system 380 projects the composite lightexiting the cross dichroic prism 360 onto a screen SC. By means of this,a color image is displayed on the screen SC.

[0081] By the way, in projector 1000 of the present embodiment, the λ/2retardation plates 166 constituting the polarization generating opticalsystem 160 (FIGS. 3(A) and 3(B)) are optical elements that convertincident linearly polarized light into linearly polarized light whosepolarization direction is perpendicular, and output it. The firstpolarizing plates 320Ri, 320Gi, 320Bi and the second polarizing plates320Ro, 320Go, 320Bo constituting the liquid crystal light valves 300R,300G, 300B (FIG. 4) are optical elements that output only apredetermined single kind of linearly polarized light. The liquidcrystal panels 310R, 310G, 310B constituting the liquid crystal lightvalves are optical elements that convert the polarization state oflinearly polarized light entering the liquid crystal panels in responseto image information, and output it. In other words, these opticalelements are polarization control elements for controlling thepolarization state of light exiting from the polarization controlelements. Also, with the polarization control elements of the presentembodiment, the control of the polarization state of exiting light isachieved by means of organic material. Thus, when light passes throughthe organic material, the polarization control elements generate heat.If the temperature of the polarization control elements becomesrelatively high, there may be the problems of degraded opticalproperties or shortened life.

[0082] Therefore, in this embodiment, the polarization control elementsare stuck to light-transmissive members of relatively high thermalconductivity.

[0083] That is, the λ/2 retardation plates 166 are stuck tolight-transmissive member 164 c. The first polarizing plates 320Ri,320Gi, 320Bi are stuck to the light-transmissive substrate 321, andsecond polarizing plates 320Ro, 320Go, 320Bo are stuck to thelight-transmissive members (right angle prisms) 360 a-360 c constitutingthe cross dichroic prism 360. The liquid crystal panels 310R, 310G, 310Bare stuck to the pair of the light-transmissive substrates 311, 312. Bysticking polarization control elements to transmissive members ofrelatively high thermal conductivity in this way, the temperature risedue to heat generation of the polarization control elements can bereduced.

[0084] In this embodiment, sapphire members having thermal conductivityof about 42 W/(m·K) are used as the aforementioned light-transmissivemembers.

[0085] Sapphire is a uniaxial single crystal whose axis called the caxis is the optic axis. When linearly polarized light enters such auniaxial crystal, the polarization state may be changed in someinstances due to birefringence. However, if the direction of travel ofthe linearly polarized light is substantially perpendicular to the opticaxis (c axis) and the electrical vector of the linearly polarized lightis substantially parallel or perpendicular to the optic axis (c axis),the linearly polarized light is output with substantially no change inpolarization state. In this embodiment, as explained in FIGS. 3(A) and3(B), the polarization generating optical system 160 outputssubstantially one kind of linearly polarized light (s-polarized light).The electrical vector of this linearly polarized light oscillates in thez direction in the drawing. Therefore, the optic axes of the sapphireforming the light-transmissive member 164 c, the light-transmissivesubstrate 321, the light-transmissive members (right angle prisms) 360a-360 c constituting the cross dichroic prism, and thelight-transmissive substrates 311, 312 will preferably be set to the zdirection in the drawing, for example. By so doing, linearly polarizedlight entering the sapphire members will be output with substantially nochange in polarization state.

[0086] In this embodiment, sapphire members are used aslight-transmissive members, but instead rock crystal or the like couldbe used. Here, “rock crystal” is a single crystal of SiO₂, a uniaxialcrystal like sapphire. The thermal conductivity of rock crystal isdifferent in the direction parallel to the optic axis (called the zaxis) and the direction perpendicular thereto, being about 9.3 (W/(m·K))in the direction parallel to the optic axis and about 5.4 (W/(m·K)) inthe direction perpendicular to the optic axis. In the case that a rockcrystal member is used, it will also be preferable to set the optic axisof the rock crystal to the z direction in the drawing, for example. Byso doing, linearly polarized light entering the rock crystal memberswill be output with substantially no change in polarization state. Also,by setting the optic axis of the rock crystal to the z direction in thedrawing, the optic axis of the rock crystal will be set to substantiallyparallel to the surface of the polarization control element. In thiscase, it will be possible to reduce the temperature rise of thepolarization control element, and to make the in-plane temperaturedistribution of the polarization control element more uniform, ascompared to the case where the optic axis of the rock crystal is set tosubstantially perpendicular to the surface of the polarization controlelement. This phenomenon is due to differences in thermal conductivityof rock crystal with respect to the optic axis.

[0087] In this way, sapphire members, rock crystal members or the likecan be used as light-transmissive members. Generally, it is preferableto use light-transmissive members of thermal conductivity of at leastabout 5.0 W/(m·K).

[0088] By the way, the projector 1000 of FIG. 1 actually comprises achassis, and the optical components are housed in the chassis.Specifically, the optical components are mounted on a base frame, andthen housed in the chassis. In this embodiment, in order to furtherreduce the temperature rise of the polarizing plates and otherpolarization control elements, particular relationship have beendesigned between the polarization control components including thepolarization control elements, and the base frame and/or chassis.

[0089]FIG. 6 is a schematic sectional view showing a typical base frame600 and a chassis 800 of projector 1000. As shown in the drawing, theoptical components are mounted on the base frame 600, and the base frame600 is housed in the chassis 800.

[0090] In FIG. 6, some of all of the optical components arranged on theoptical path from the illumination optical system 100 to the projectionoptical system 380 shown in FIG. 1 are shown housed in the chassis 800,but actually all of the optical components are housed in the chassis800. Specifically, the depiction in FIG. 6 focuses on green coloredlight G, and shows the optical components constituting the illuminationoptical system 100, the field lens 234, the optical componentsconstituting the second liquid crystal light valve 300G, the crossdichroic prism 360, and the projection optical system 380. Also, in FIG.6 the polarization control components including polarization controlelements 166, 320Gi, 310G, or 320Go are shown with solid lines, andother optical components are shown with broken lines.

[0091] All optical components, excluding the light source device 120,are mounted inside the base frame 600. The light source device 120 ismounted in a separately prepared the light source case 650.

[0092] The base frame 600 is a frame having a roughly concave crosssection defined by side portions and a bottom portion, and its outsideshape when viewed from the z direction is a shape enclosing a series ofoptical components shown in FIG. 1. The bottom portion of the base frame600 is provided on its top face with two convex portions 601, 602, andon its bottom face with a cooling fin 610. The base frame 600 isintegrally molded of metal material.

[0093] The cross dichroic prism 360 is mounted on the first convexportion 601, and the projection optical system 380 is mounted on thesecond convex portion 602. On the bottom portion of the base frame 600,other optical components are mounted via holders. Specifically, opticalcomponents are held by holders, and the holders are fixed to the bottomportion of the base frame 600. In this embodiment, the holders, like thebase frame 600, are formed using metal material.

[0094] In particular, the first polarization control componentconsisting of the polarization generating optical system 160 only ismounted on the base frame 600 via a first holder 710. The secondpolarization control component consisting of the first polarizing plate320Gi and the light-transmissive substrate 321 is mounted on the baseframe 600 via a second holder 720. The third polarization controlcomponent consisting of the liquid crystal panel 310G and the pair oflight-transmissive substrates 311, 312 is mounted on the base frame 600via a third holder 730. Also, the fourth polarization control componentconsisting of the second polarizing plate 320Go and the cross dichroicprism 360 is mounted on the base frame 600 by sticking the bottom faceof the cross dichroic prism 360 to the first convex portion 601 of thebase frame 600.

[0095]FIG. 7 is an explanatory diagram of the first holder 710 thatholds the first polarization control component consisting ofpolarization generating optical system 160 only. As shown in thedrawing, the holder 710 comprises a fixing section 712 and an attachingsection 714. The fixing section 712 has a cross sectional shape of aroughly L-shape, and a roughly rectangular opening on the face throughwhich light passes. The attaching section 714 has a cross sectionalshape of a roughly concave shape, and a roughly rectangular opening onthe face through which light passes. The fixing section 712 and theattaching section 714 are joined together with the first polarizationcontrol component 160 sandwiched between. Specifically, four attachmentscrews 716 are passed through holes provided in the four corners ofattaching section 714, and screwed into female threads provided in thefour corners of the fixing section 712, so as to join the fixing section712 and the attaching section 714. The first holder 710 is then fixed tothe base frame 600 by screwing the fixing section 712 onto the baseframe 600.

[0096]FIG. 8 is an explanatory diagram of the second holder 720 thatholds the second polarization control component consisting of the firstpolarizing plate 320Gi and the light-transmissive substrate 321. Asshown in the drawing, the holder 720 comprises a fixing section 722 andan attaching section 724 similar to FIG. 7. As in FIG. 7, the fixingsection 722 and the attaching section 724 are joined together by fourattachment screws 726, with the second polarization control component320Gi, 321 sandwiched between. The second holder 720 is then fixed tothe base frame 600 by screwing the fixing section 722 onto the baseframe 600.

[0097]FIG. 9 is an explanatory diagram of the third holder 730 thatholds the third polarization control component consisting of the liquidcrystal panel 310G and the pair of light-transmissive substrates 311,312. As shown in the drawing, the holder 730 comprises a fixing section732 and an attaching section 734. The fixing section 732 is similar tothe fixing section 712 in FIG. 7. The attaching section 734 has a frameshape. As in FIG. 7, the fixing section 732 and the attaching section734 are joined together by four attachment screws 736, with the thirdpolarization control component 310G, 311, 312 sandwiched between. Thethird holder 730 is then fixed to the base frame 600 by screwing thefixing section 732 onto the base frame 600.

[0098] As shown in FIG. 6, all optical components, excluding the lightsource device 120, are mounted inside the base frame 600 via holders,and the light source device 120 is mounted independently in a lightsource case 650. Light source case 650 has relatively large holes 651,652 in its upper portion and lower portion. The light source case 650 isfixed to the base frame 600 via a connector 660. The light source case650 and the connector 660 are heat insulating members formed using heatinsulating material (that is, material of relatively low thermalconductivity).

[0099] In the manner described above, optical components are mountedinside the base frame 600, and the base frame 600 is housed in thechassis 800.

[0100] The chassis 800 (FIG. 6) is comprised of an upper chassis 810 anda lower chassis 820. The upper chassis 810 and lower chassis 820 areeach integrally molded using metal material. The upper chassis 810 isprovided in three locations with hole groups 811, 812, 813, therespective hole groups 811, 812, 813 being arranged above the lightsource device 120, the polarization generating optical system 160, andthe liquid crystal light valve 300G. Heat generated by the λ/2retardation plates 166 can escape by means of the second hole group 812,and heat generated by the polarizing plate 320Gi, 320Go and the liquidcrystal panel 310G can escape by means of the third hole group 813. Thelower chassis 820 is also provided in three locations with hole groups821, 822, 823. The lower chassis 820 is also provided with two convexportions 826, 827 facing to the inside of chassis 800. Actually, moreconvex portions are provided. The base frame 600 on which the opticalcomponents have been mounted is placed on the convex portions 826, 827of the lower chassis 820 and fixed by screwing on. A gap between thelower chassis 820 and the base frame 600 is formed by the convexportions 826, 827 of the lower chassis 820, and two cooling fans 410,420 are arranged in the gap. The first cooling fan (axial fan) 410 isarranged below the light source device 120, and the second fan (siroccofan) 420 is arranged in proximity to below the liquid crystal lightvalve 300G.

[0101] The first cooling fan 410 generates a breeze passing through thehole group 811 provided in the upper chassis 810, the two holes 651, 652provided in the light source case 650, and the hole group 821 providedin the lower chassis 820. In this way, the light source device 120 canbe cooled.

[0102] The second cooling fan 420 generates a breeze passing through thehole group 822 provided in the lower chassis 820, a hole provided in theconvex portion 827, and the hole group 823. This breeze hits the coolingfin 610 provided on the base frame 600. In this way, the base frame 600can be cooled efficiently.

[0103] As described above, in this embodiment the holders 710, 720, 730that hold the optical components, the base frame 600, and the chassis800 are formed using metal material. By so doing, heat generated by thepolarization control elements 166, 320Gi, 310G and 320Go in particularcan efficiently escape from the chassis.

[0104] Specifically, the light-transmissive member 164c to which the λ/2retardation plates 166 are stuck is held in a state of contact withfirst holder 710. Similarly, the light-transmissive substrate 321 towhich the first polarizing plate 320Gi is stuck is held in a state ofcontact with second holder 720, and the pair of light-transmissivesubstrates 311, 312 to which the liquid crystal panel 310G is stuck isheld in a state of contact with third holder 730. Thus, heat generatedby the three polarization control elements 166, 320Gi, 310G istransferred to the metal base frame 600 via the light-transmissivemembers 164 c, 321, 311, 312 formed of sapphire, and the metal holders710, 720, 730.

[0105] Meanwhile, the cross dichroic prism 360 including thelight-transmissive member (right angle prism) to which the secondpolarizing plate 320Go is stuck is stuck to the first convex portion 601provided to the base frame 600. Thus, heat generated by the secondpolarizing plate 320Go is transferred to the metal base frame 600 viathe light-transmissive members (right angle prisms) 360 a-360 d formedof sapphire.

[0106] In this way, in this embodiment the light-transmissive members164 c, 321, 311, 312, 360 b to which the polarization control elements166, 320Gi, 310G, 320Go are stuck are thermally coupled to the baseframe 600. Thus, it is possible to reduce the temperature rise occurringwith heat generation of the polarization control elements.

[0107] Also, in this embodiment, the metal base frame 600 contacts themetal chassis 800 via convex portions 826, 827 provided to the lowerchassis 820. That is, the base frame 600 and the chassis 800 arethermally coupled. Thus, heat generated by the polarization controlelements 166, 320Gi, 310G, 320Go is transferred from the base frame 600to the chassis 800. In this way, it is possible to reduce thetemperature rise occurring due to heat generation of the polarizationcontrol elements 166, 320Gi, 310G, 320Go.

[0108] Further, as mentioned above, in this embodiment, the light sourcecase 650 and the connector 660 are formed using heat insulatingmaterial, so the light source device 120 and the base frame 600 arethermally insulated. Thus, while the light source device 120 per segenerates heat markedly, the temperature rise of the base frame 600 dueto heat generation of the light source device 120 can be reduced.Further, the light source device 120 is cooled by the first cooling fan410, so that the surrounding temperature of the light source device 120can be reduced, and the temperature rise of the base frame 600 can bereduced. By reducing the temperature rise of the base frame 600 due toheat generation of the light source device 120 in this way, heat of thepolarization control elements 166, 320Gi, 310G, 320Go can be transferredefficiently to the holders 710, 720, 730, the base frame 600 and thechassis 800. As a result, it is possible to efficiently reduce thetemperature rise due to heat generation of the polarization controlelements.

[0109] Mg alloys or Al alloys may be used, for example, as metalmaterials to form the holders 710, 720, 730 that hold the opticalcomponents, the base frame 600 and chassis 800. UP (unsaturatedpolyester resin) or PPS (polyphenylene sulfide) may be used, forexample, as heat insulating materials to form the light source case 650and connector 660.

[0110] As explained above, the projector 1000 of this embodiment iscomprised of polarization control components that include polarizationcontrol elements including organic material for controlling polarizationstate of light exiting from the polarization control components, andlight-transmissive members having thermal conductivity of at least about5.0 W/(m·K), to which polarization control elements are stuck. Theprojector 1000 is also comprised of a metal base frame 600 on which aplurality of optical components are mounted. The light-transmissivemembers and the base frame are thermally coupled. By so doing, heat ofthe polarization control elements can be transferred to thelight-transmissive members and base frame, so that it is possible toreduce the temperature rise due to heat generation of the polarizationcontrol elements.

[0111] It should be noted that, in this specification, “thermallycoupled” state means a state in which heat is relatively easilytransferred. The state of the light-transmissive member and the baseframe being thermally coupled includes a state in which, as with thesecond polarizing plate 320Go shown in FIG. 6 for example, thelight-transmissive members 360 a-360 d and the base frame 600 aremutually contacted, or a state in which, as with the first polarizingplate 320Gi shown in FIG. 6 for example, a member of relatively highthermal conductivity (holder 720) contacting both the light-transmissivemember 321 and the base frame 600 is interposed.

[0112] A-1. Modification of First Embodiment:

[0113] In the First Embodiment, the fourth polarization controlcomponent consisting of the polarizing plate and the cross dichroicprism is fixed to the first convex portion 601 by means of an adhesivesheet or adhesive. As explained in FIGS. 7-9, the first through thirdpolarization control components are fixed to holders by screwing, butinstead of this, or in addition to this, they could be fixed to holdersby means of an adhesive sheet or adhesive. Specifically,light-transmissive members and fixing sections are joined by means of anadhesive sheet or adhesive, and light-transmissive members and attachingsections are joined by means of an adhesive sheet or adhesive. Also, theholders (fixing sections) holding the first through third polarizationcontrol components are fixed to the base frame by screwing, but insteadof this, or in addition to this, they could be fixed to the base frameby means of an adhesive sheet or adhesive, or by metal welding.

[0114] Material having relatively high thermal conductivity of at leastabout 0.4 W/(m·K) is preferred as the adhesive sheet, and preferablycontains copper or other metal foil. Teraoka Seisakusho Co., Ltd.'s No.792 (about 0.753 W/(m·K)), No. 7090 (about 0.419 W/(m·K)), for example,may be used as the adhesive sheet.

[0115] As the adhesive it is preferable to use one having relativelyhigh thermal conductivity of at least about 0.1 W/(m·K). Dow CorningToray Silicone Co., Ltd.'s SE4450 (about 1.97 W/(m·K)), Three Bond Co.,Ltd.'s No. 3305B, for example, may be used as the adhesive. It ispreferable to form the adhesive layer with relatively small thickness,for example, it is preferable to form it with thickness of about 10 μmor less.

[0116] Also, in the case of employing brazing and soldering as metalwelding, it is preferably to use flux having a relatively high thermalconductivity of at least about 0.4 W/(m·K). As the flux, solder (about40-50 W/(m·K)) may be used.

[0117] As mentioned above, when an adhesive sheet of relatively smallthickness or an adhesive is interposed between a light-transmissivemember and a holder (fixing section and/or attaching section), thelight-transmissive member and the holder are not directly contacting butare close. Also when an adhesive sheet of relatively small thickness oran adhesive is interposed between a holder (fixing section) and a baseframe, the holder and the base frame are not directly contacting but areclose. Therefore, in this case as well, heat generated by thepolarization control elements can be transferred to the base frame.Also, where a holder and base frame are joined by metal welding, heatgenerated by polarization control elements can be transferredefficiently to the base frame.

[0118] That is, the “thermally coupled” state is a state in which heatbeing transferred relatively easily, and includes a state in which anadhesive sheet of relatively small thickness or an adhesive isinterposed between a light-transmissive member and the base frame.

[0119] B. Second Embodiment:

[0120] In the First Embodiment, as shown in FIGS. 6 and 8, the firstpolarizing plate 320Gi, together with the light-transmissive substrate321, constitutes a polarization control component, but instead of this,the plate 320Gi, together with the field lens 234, may constitute apolarization control component.

[0121]FIG. 10 is an explanatory diagram showing a field lens 234′ withthe first polarizing plate 320Gi stuck to it. This field lens 234′ isformed of sapphire. As shown in the drawing, the first polarizing plate320Gi is stuck to the flat face of the plano-convex field lens 234′.

[0122]FIG. 11 is an explanatory diagram showing a holder 750 that holdsa polarization control component consisting of the first polarizingplate 320Gi and the field lens 234′ shown in FIG. 10. The holder 750comprises a metal fixing section 752 and an attaching section 754. Thefixing section 752 has a cross sectional shape of a roughly L-shape, anda roughly circular opening on the face through which light passes. Theattaching section 754 has a cross sectional shape of a roughly concaveshape, and a roughly circular opening on the face through which lightpasses. As in FIG. 8, the fixing section 752 and the attaching section754 are joined together by four attachment screws 756, with polarizationcontrol component 320Gi, 234′ sandwiched between. The holder 750 is thenfixed to the base frame 600 by screwing the fixing section 752 onto thebase frame 600.

[0123] In this embodiment as well, the field lens 234′ with the firstpolarizing plate 320Gi stuck to it is held in a state of contact withthe holder 750. Thus, heat generated by the first polarizing plate 320Giis transferred to the metal base frame 600 via the field lens 234′formed of sapphire, and the metal holder 750. Also, heat generated bythe first polarizing plate 320Gi is transferred from the metal baseframe 600 to the metal chassis 800.

[0124] Even where a polarization control component consists of a firstpolarizing plate (polarization control element) 320Gi and field lens234′ formed of sapphire in the manner described above, the temperaturerise due to heat generation of the first polarizing plate 320Gi can bereduced. Also, in this case the light-transmissive substrate 321 and theholder 720 of FIG. 6 can be omitted.

[0125] By the way, in FIG. 10, the field lens 234′ is formed ofsapphire, and since the hardness of sapphire is relatively high,processing of lens faces is relatively difficult. Therefore, the lensfaces of the field lens can be formed using other material.

[0126]FIG. 12 is an explanatory diagram showing a first modification ofa field lens with a first polarizing plate 320Gi stuck to it. As shownin the drawing, this field lens 234A comprises a plastic lens 234A1 anda light-transmissive substrate 234A2 formed of sapphire. The plasticlens 234A1 is obtained by injection molding.

[0127] Of the two faces of light-transmissive substrate 234A2, the facecontacting the plastic lens 234A1 may have a relatively rough surface.In this case, the irregularity of the rough surface will be filled withadhesive, so that irregular reflection of light by the rough surface canbe prevented, and also to increase the bonding strength of the plasticlens 234A1 and the light-transmissive substrate 234A2.

[0128]FIG. 13 is an explanatory diagram showing a second modification ofa field lens with a first polarizing plate 320Gi stuck to it. As shownin the drawing, this field lens 234B comprises a plastic lens 234B1 anda light-transmissive substrate 234B2 formed of sapphire, as in FIG. 12.However, in FIG. 13, the plastic lens 234B1 is formed so as to envelopone surface of the light-transmissive substrate 234B2. By so doing, thebonding strength of the plastic lens 234B1 and the light-transmissivesubstrate 234B2 can be further increased.

[0129] Even where the field lens 234A, 234B shown in FIG. 12 or FIG. 13is used, the light-transmissive substrate 234A2 or 234B2 with the firstpolarizing plate 320Gi stuck to it is held in a state of contact withthe holder 750. Thus, heat generated by the first polarizing plate 320Giis transferred to the metal base frame 600 via the light-transmissivesubstrate 234A2 or 234B2 formed of sapphire, and the metal holder 750.The heat is then transferred from the metal base frame 600 to the metalchassis 800.

[0130] Even where a field lens 234A or 234B of a plastic lens 234A1 or234B1 provided over a tabular light-transmissive member 234A2 or 234B2is used, temperature rise due to heat generation of the first polarizingplate 320Gi can be reduced. Also, as compared to the case of using thefield lens 234′ of FIG. 10, there is no need to form the lens faces ofsapphire, which has the advantage of being able to easily fabricate thefield lenses 234A, 234B.

[0131] With the field lenses 234A, 234B of FIGS. 12 and 13, plasticlenses are used, but glass lenses formed of ordinary glass could be usedas well. If a polarization plate is stuck directly onto a plastic lensor glass lens, heat generated by the polarization plate can, in someinstances, create temperature non-uniformity in the lens, or produceoptical distortion. However, by forming the plastic lens or glass lenson one face of a tabular light-transmissive member formed of sapphire,and sticking the polarizing plate to the other face, it is possible tosignificantly reduce optical distortion of the plastic lens or glasslens.

[0132] B-1. Modification of Second Embodiment:

[0133] In the Second Embodiment, as explained in FIG. 11, thepolarization control component including the polarizing plate 320Gi isfixed to the holder by screwing, but instead of this, or in addition tothis, it could be fixed to the holder by means of an adhesive sheet oradhesive. Also, the holder (fixing section) holding the polarizationcontrol component is fixed to the base frame by screwing, but instead ofthis, or in addition to this, it could be fixed to the base frame bymeans of an adhesive sheet or adhesive, or by metal welding.

[0134] C. Third Embodiment:

[0135] In the First Embodiment, as shown in FIGS. 6 and 9, the thirdpolarization control component consisting of the liquid crystal panel310G and the pair of light-transmissive substrates 311, 312 is held bythe holder 730, and the holder 730 is directly fixed to the base frame600, but the holder could also be fixed to the base frame 600 via someother part.

[0136]FIG. 14 is an explanatory diagram showing a holder 730A that holdsthe third polarization control component consisting of the liquidcrystal panel 310G and the pair of light-transmissive substrates 311,312. The holder 730A is substantially similar to the holder 730 of FIG.9, but a fixing section 732A is modified. Specifically, the fixingsection 732A of this embodiment has two projecting portions.

[0137] As explained in FIG. 9, the fixing section 732A and attachingsection 734 are joined together with the third polarization controlcomponents 310G, 311, 312 sandwiched between. Also, in this embodimentthe holder 730A is fixed to the base frame 600 by sticking the holder730A to the second right angle prism 360b of the cross dichroic prism360. Specifically, the two projecting portions of the fixing section734A are stuck at the sides of the polarizing plate 302Go stuck to thesecond right angle prism 360 b.

[0138] In this embodiment as well, the pair of light-transmissivesubstrates 311, 312 with the liquid crystal panel 310G stuck is held ina state contacted with the third holder 730A. Therefore, heat generatedby the liquid crystal panel 310G is transferred to thelight-transmissive member 360 b formed of sapphire, via thelight-transmissive substrates 311, 312 formed of sapphire and the metalholder 730A. The heat is then transferred to the metal base frame 600and the metal chassis 800 via the light-transmissive members 360 a-360 dformed of sapphire. In this way as well, the temperature rise due toheat generation of liquid crystal panel 310G can be reduced.

[0139] As explained above, even if a holder holding a polarizationcontrol component is fixed to the base frame via other member ofrelatively high thermal conductivity, the temperature rise due to heatgeneration of polarization control element can be reduced. Generally,where a holder is used, the base frame and light-transmissive member towhich a polarization control element is stuck will be thermally coupledat least via the holder.

[0140] In this way, a “thermally coupled” state of a light-transmissivemember and base frame in the present invention includes, for example, astate in which, as with the liquid crystal panel 310G shown in FIG. 14,there is interposed a set of members (specifically, members consistingof the holder 730A and the light-transmissive members 360 a-360 d formedof sapphire) of relatively high thermal conductivity, contacting boththe light-transmissive members 311, 312 and the base frame 600.

[0141] D. Fourth Embodiment:

[0142]FIG. 15 is an explanatory diagram showing a chassis 800A in theForth Embodiment. This chassis 800A is substantially similar to thechassis 800 shown in FIG. 6, but is provided with convex portions 819,829 above and below the first lens array 140. Specifically, a firstconvex portion 819 facing to the inside of chassis 800A is provided tothe upper chassis 810A, and a second convex portion 829 facing to theinside of the chassis 800A is provided to the lower chassis 820A. Thefirst convex portion 819 reaches substantially to the upper edge ofholder 790 that holds the first lens array 140, and the second convexportion 829 reaches substantially to the bottom face of the bottomportion of base frame 600.

[0143] The holder 790 that holds the first lens array 140 has a crosssectional shape of a roughly L-shape, and is provided with a roughlyrectangular opening on the face through which light passes. The firstlens array 140 is stuck to the holder 790, and the holder 790 is fixedto the base frame 600.

[0144] As shown in the drawing, the interior of the chassis 800 isdivided by means of the two convex portions 819, 829, the first lensarray 140 and the holder 790 into a first area W1 housing the lightsource device 120, and another second area W2. By dividing the interiorof the chassis 800 into two areas in this way, air heated by the lightsource device 120 can be prevented from flowing out from the first areaWI into the second area W2. Thus, it is possible to further reduce thetemperature rise of polarization control elements 166, 320Gi, 310G,320Go housed in the second area W2.

[0145] E. Fifth Embodiment:

[0146] In the First Embodiment, as shown in FIG. 6, optical componentsare held by individually prepared holders, but instead a plurality ofoptical components could be held by a common holder.

[0147] FIGS. 16(A) and 16(B) are explanatory diagrams showing a holder701 that holds a plurality of optical components included in theillumination optical system 100. The holder 701 is integrally moldedusing metal material. As shown in the drawing, the holder 701 holdsfirst and second lens arrays 140, 150, a polarization generating opticalsystem 160, and a superimposing lens 170. FIG. 16(A) is a perspectiveview of the holder 710 when viewed from the first lens array 140 end,and FIG. 16(B) is a perspective view of the holder 710 when viewed fromthe superimposing lens 170 end.

[0148] As shown in FIGS. 16(A) and (B), the holder 701 has an outershape of substantially cuboid shape, and has an open face through whichoptical components are inserted into the holder 701 from above (zdirection). Also, the light incident face on which the first lens array140 is mounted and the light exiting face on which the superimposinglens 170 is mounted are provided with openings. On the holder 701,convex portions and concave portions that determine the position of eachoptical component 140, 150, 160, 170 are formed facing to the inside ofthe holder 701, extending from the upper face to the lower face of theholder 701. These convex portions and concave portions are provided aspairs on opposing side faces of the holder 701.

[0149] In this embodiment as well, the polarization generating opticalsystem 160 including the light-transmissive member 164 c to which theλ/2 retardation plates 166 are stuck is held in a state of contact withthe holder 701. Therefore, heat generated by the λ/2 retardation plates166 is transferred to the metal base frame 600 via thelight-transmissive members 164 c formed of sapphire and the metal holder701. The heat is then transferred from the metal base frame 600 to themetal chassis 800. In this way, even if the holder 701 that holds incommon a plurality of optical components is used, the temperature risedue to heat generation of the polarization control elements 166 can bereduced.

[0150] In this embodiment, the case of a plurality of optical componentsincluded in the illumination optical system 100 being held by a commonholder was described, but another plurality of optical components couldbe held by another common holder.

[0151] Also, in this embodiment, polarization control componentsincluding the λ/2 retardation plates 166 are fixed to the common holder710 by means of an adhesive sheet or adhesive. Also, in this embodiment,the common holder is fixed to the base frame by screwing, but instead ofthis, or in addition to this, it could be fixed to the base frame bymeans of an adhesive sheet or adhesive, or by metal welding.

[0152] F. Sixth Embodiment:

[0153]FIG. 17 is a simplified perspective diagram showing a base frame600B on which optical components of projector will be mounted in theSixth Embodiment. The Base frame 600B, like the base frame 600 in theFirst Embodiment (FIG. 6), has a shape so as to enclose the series ofoptical components shown in FIG. 1. However, unlike the base frame 600of the First Embodiment, the base frame 600B of this embodimentcomprises in the end portion thereof a light source mounting section608B having an outer shape of substantially cuboid shape. The base frame600B including the light source mounting section 608B is integrallymolded using metal material of relatively high thermal conductivity (forexample, Mg alloy having thermal conductivity of about 156 W/(m·K) or Alalloy having thermal conductivity of about 237 W/(m·K)). The base frame600B, excluding the light source mounting section 608B, has an open faceat the upper face thereof, but the light source mounting section 608Bhas an open face at the lower face thereof

[0154] The inside face of the side portions of the base frame 600B hasconvex portions for mounting optical components. On the inside face(upper face) of the bottom portion 600Bb of the base frame 600B projectsup a column shaped portion having concavities and convexities, in whichoptical components are mounted. Also, the inside face of the bottomportion 600Bb of base frame 600B is provided with a convex portion 601Bfor mounting a cross dichroic prism. At a peripheral side of the convexportion 601B is formed a relatively low area W, and in this area W threerelatively large roughly rectangular holes 620R, 620G, 620B are formed.

[0155]FIG. 18 is a simplified perspective diagram showing the base frame600B on which the optical components of projector have been mounted. Asshown in the drawing, the base frame 600B has mounted thereon variousoptical components that make up the illumination optical system 100′,the color separation optical system 200, the relay optical system 220,the liquid crystal light valves 300R, 300G, 300B, the cross dichroicprism 360, the projection optical system 380 etc.

[0156] As explained in FIG. 2, in the illumination optical system 100 ofthe First Embodiment, the light source device 120 is comprised of a lamp122, a reflector 124 and a parallelizing lens 126, but in theillumination optical system 100′ of this embodiment, light source device120′ is comprised of a lamp 122 and a reflector 124 only.

[0157] The light source device 120′ is housed in a light source case650B having a roughly concave cross section defined by side portions anda bottom portion, and then mounted inside the light source mountingsection 608B. Also, the parallelizing lens 126 is mounted directly onthe base frame 600B, and the illumination optical system 100′ excludingthe light source device 120′ and the parallelizing lens 126 is mountedon the base frame 600B, in a state held by the holder 701B as shown inFIGS. 16(A) and 16(B).

[0158] The light source case 650B, as in the First Embodiment, is formedof a heat insulating material having relatively low thermal conductivity(for example, the above-mentioned UP or PPS). However, in thisembodiment, the upper face of light source case 650B is an open face.Because of this, heat of the light source device 120′ is relativelyeasily transferred to the light source mounting section 608B of the baseframe 600B. Thus, in this embodiment, the inside wall of the lightsource mounting section 608B is provided with a heat insulating member(not shown). A member having thermal conductivity of no more than about0.1 W/(m·K) is preferred to be used as the heat insulating member, forexample, a heat insulating member formed of ceramic material or siliconetype forming material can be used. As ceramic materials, ceramics andceramic composite materials (such as composite materials of ceramicfibers and rock wool and alumina fibers and carbon fibers) can be used.As silicone type forming materials, silicone rubber or silicone spongecan be used. The inside wall of light source mounting section 608B canalso be coated with ceramic film. Generally, the heat insulating memberwill be arranged in the space between the light source device and thebase frame. By so doing, the light source device 120′ and the base frame600B can be thermally isolated, so temperature rise of the base framedue to heat generation of the light source device can be reduced. As aresult, heat generated by the polarization control elements can beefficiently transferred to the base frame.

[0159]FIG. 19 is an explanatory diagram showing a third holder 730B thatholds a third polarization control component consisting of liquidcrystal panel 310G and a pair of light-transmissive substrates 311, 312in the Sixth Embodiment. The holder 730B comprises a metal fixingsection 732B and an attaching section 734B.

[0160] The fixing section 732B comprises a frame portion 732B1 andcolumn shaped portions 732B2 projecting up in proximity to the fourcorners of the frame portion 732B1. Each column shaped portion 732B2 hasa first round column portion B2 a having a relatively large diameter,and a second round column portion B2 b having a relatively smalldiameter. Also, the distal end of each column shaped portion 732B2, morespecifically, the distal end of each second round column portion B2 b,has a male thread. The attaching section 734B comprises two partialattaching sections 734B1, 734B2. The first partial attaching section734B1 is the same as the attaching section 734 of FIG. 9. The secondpartial attaching section 734B2 has a frame shape. At the four cornersof the two partial attaching sections 734B1, 734B2, holes are providedhaving diameter smaller than the first round column portion B2 a of thecolumn shaped portion 732B2, and larger than the second round columnportion B2 b.

[0161] The two partial attaching sections 734B1, 734B2 are joinedsandwiching the third polarization control component 310G, 311, 312.Also, the column shaped portions 732B2 of the fixing section 732B arepassed through the holes at the four corners of the attaching section734B. After this, four attaching screws 736B are screwed onto the malethreads at the distal ends of the column shaped portions 732B2 so as tojoin the fixing section 732B and the attaching section 734B. Then, thethird holder 730B is fixed to the base frame 600 by means of stickingthe holder 730B to the second right angle prism 360 b of the crossdichroic prism 360.

[0162] In this embodiment as well, the pair of light-transmissivesubstrates 311, 312 to which the liquid crystal panel 310G is stuck areheld in a state of contact with the third holder 730B. Thus, heatgenerated by the liquid crystal panel 310G is transferred to thelight-transmissive member 360 b formed of sapphire, via thelight-transmissive substrates 311, 312 formed of sapphire and the metalholder 730B. The heat is then transferred to the metal base frame 600Bvia the light-transmissive members 360 a-360 d formed of sapphire. Inthis way as well, as in FIG. 14, the temperature rise due to heatgeneration of the liquid crystal panel 310G can be reduced.

[0163]FIG. 20 is a perspective diagram showing the situation in which abase frame cover 680B is attached to the base frame 600B of FIG. 18. Thebase frame cover 680B, like the base frame 600B, is integrally moldedfrom metal material. As shown in the drawing, this base frame cover 680Bis formed so as to cover the illumination optical system 100′, the colorseparation optical system 200, and the relay optical system 220. To theupper face of base frame cover 680B are attached three mirror adjustingmechanisms 204AD, 208AD, 228AD that adjust the angles of three mirrors204, 208, 228 situated closest to the three liquid crystal light valves300R, 300G, 300B. Mirror adjusting mechanisms can also be provided so asto adjust the angles of other mirrors, for example, the dichroic mirrors202 and the reflecting mirror 224.

[0164] As shown in FIGS. 18 and 20, the optical components of theprojector are mounted inside the base frame 600B and then housed in thechassis. FIG. 21 is an explanatory diagram showing the outside ofchassis 800B. The chassis 800B comprises an upper chassis 810B and alower chassis 820B, the upper chassis 810B and the lower chassis 820Beach being integrally molded using metal material. Two sets of slitgroups 811B, 812B are provided to the upper chassis 810B.

[0165]FIG. 22 is an explanatory diagram showing the condition of theinterior of the chassis 800B shown in FIG. 21. Within the chassis 800Bare housed the base frame 600B and two cooling fans 410B, 420B.Actually, the chassis 800B also houses a power supply section thatsupplies electrical power to the light source device 120′, the liquidcrystal light valves 300R, 300G, 300B, as well as a controller thatcontrols these, and the like.

[0166] In this embodiment too, the metal base frame 600B, in the samemanner as in the First Embodiment (FIG. 6), contacts a metal base frame800B via a convex portions (connecting portions), not shown here,provided to the lower chassis 820B, and the base frame 600B and chassis800B are thermally coupled. Because of this, heat generated bypolarization control elements is transferred from the base frame 600B tothe chassis 800B, as a result of which it is possible to further reducethe temperature rise due to heat generation of the polarization controlelements.

[0167] The first cooling fan (axial fan) 410B is arranged above thecross dichroic prism 360 (FIG. 20). The first cooling fan 410B generatesa breeze moving from the outside of chassis 800B to the inside throughthe first slit group 811B of the upper chassis 810B. The second coolingfan (sirocco fan) 420B is arranged so as to be next to the light sourcemounting section 608B on which the light source device 120′ is mounted.The second cooling fan 420B generates a breeze moving from the inside ofthe chassis 800B to the outside through the second slit group 812B ofthe upper chassis 810B. That is, as shown in FIG. 21, the breezeintroduced from the outside by the first cooling fan 410B is expelled tothe outside by means of the second cooling fan 420B.

[0168]FIG. 23 is an explanatory diagram showing the situation around thefirst cooling fan 410B shown in FIG. 22. FIG. 23 shows a schematic crosssectional view when the proximity of the first slit group 811B shown inFIG. 21 is cut in a plane parallel to the xz direction. The crossdichroic prism 360 is mounted on the convex portion 601B (FIG. 17)provided on the inside face of the bottom portion 600Bb of the baseframe 600B. To the side face of the cross dichroic prism 360 is stuckthe holders 730B (FIG. 19) that holds the three liquid crystal panels310R, 310G, 310B, in a state with a predetermined gap provided.

[0169] As shown in FIG. 23, in this embodiment, between the base frame600B and the lower chassis 820B, thermal conductive rubber 830B isarranged so as to contact both the base frame 600B and the lower chassis820B. Thermal conductive rubber 830B is arranged below the convexportion 601B on which the cross dichroic prism 360 is mounted, and heattransferred from the cross dichroic prism 360 to the base frame 600B istransferred to the chassis 800B via the thermal conductive rubber 830B.Even using the thermal conductive rubber in this way, the metal baseframe 600B and the metal chassis 800B can be thermally coupled. As thethermal conductive rubber 830B, a metal powder of relatively highthermal conductivity (for example, aluminum oxide or boron nitride,etc.) is added to silicone rubber can be used.

[0170] The first cooling fan 410B is arranged above the cross dichroicprism 360 by means of a holder (not shown). The breeze introduced by thefirst cooling fan 410B passes through the vicinity of the cross dichroicprism 360 and is drawn into holes 620R, 620G, 620B (FIG. 17) provided inthe bottom portion of the base frame 600B. When this happens,polarization control components including the liquid crystal panels310R, 310G, 310B, and the holders 730B holding the liquid crystal panels310R, 310G, 310B, are air cooled, so that it is possible to furtherprevent the temperature rise due to heat generation of the liquidcrystal panels. The breeze drawn into holes 620R, 620G, 620B is then ledinto an air passage AG provided in the bottom portion of the base frame600B.

[0171]FIG. 24 is an explanatory diagram showing the outside face of thebottom portion of the base frame 600B. As shown in the drawing, aplurality of cooling fins 631-633 are provided on the outside face ofthe bottom portion 600Bb of the base frame 600B. The first cooling fin631 is provided so as to enclose the area in which the cross dichroicprism 360, the liquid crystal light valves 300R, 300G, 300B, and thecolor separation optical system 200 shown in FIG. 18 are mounted. Theplurality of second cooling fins 632 are provided along a directionfacing from the cross dichroic prism 360 towards the illuminationoptical system 100′ shown in FIG. 18. The third cooling fin 633 isarranged so as to lie along the y-direction in proximity to the locationwhere the parallelizing lens 126 of the illumination optical system 100′shown in FIG. 18 is mounted. Also, the distal ends of the cooling fins631-633 have widths such that when the base frame 600B is housed insidethe lower chassis 820B (FIG. 22), the bottom portion of the lowerchassis 820B is contacted. By means of the first and third cooling fins631, 633, an air passage AG shown in FIG. 23 is constituted, between thebase frame 600B and the lower chassis 820B.

[0172] Breeze guided onto the outside face of the bottom portion 600Bbof the base frame 600B via holes 620R, 620B, 620B advances through thearea enclosed by the first and third cooling fins 631, 633 (i.e., airpassage AG), along the second cooling fin 632. Then, the breeze reachingthe proximity of the third cooling fin 633 is guided to the +y directionby means of the second cooling fan 420B (FIG. 22). After that, thebreeze in the air passage AG is expelled to outside the chassis 800B bymeans of the second cooling fan 420B.

[0173] In this way, by providing cooling fins 631-633, as in the FirstEmbodiment (FIG. 6), the base frame 600B can be cooled efficiently.Also, in this embodiment, by providing a plurality of second fins 632, aplurality of flow passages are formed. Thus, the breeze passing throughair passage AG does not readily develop turbulent flow, and as a resultof this, it is possible to even more efficiently cool the base frame600B.

[0174] By the way, in this embodiment, an oxide film is formed on theoutside face of the metal (for example, Mg alloy or Al alloy) base frame600B. The oxide film can be formed, for example, by anodic oxidationprocess. By forming an oxide film, heat of the base frame 600B can betransferred efficiently to the chassis 800B. That is, in the case wherea base frame 600B with an oxide film formed on the outside face is used,the radiation rate is higher than compared to the case of using a metalbase frame as-is. Here, radiation rate means the ratio ε (E/E′) wherethe total radiant energy of a hypothetical black body is designated E′and the total radiant energy of an object is designated E, and ratio εcan assume a value of from 0 to 1. By increasing the radiation rate ofthe base frame 600B, the temperature of the base frame 600B can be maderelatively low, so the temperature rise due to heat generation ofpolarization control elements can be further reduced.

[0175] In this embodiment, the outside face of chassis 800B (FIG. 22)also has an oxide film formed. Because of this, heat of the chassis 800Bcan be efficiently emitted to the outside, and as a result it ispossible to further reduce the temperature rise due to heat generationof polarization control elements.

[0176] In this embodiment, the outside faces of the base frame 600B andthe chassis 800B have oxide film formed on them, but instead of this,other film could be formed. For example, metal having higher radiationrate than the metal making up the base frame 600B and the chassis 800Bcould be plated onto the outside faces of the base frame 600B and thechassis 800B.

[0177] Generally, films for increasing radiation rate will be formed onthe outside faces of the base frame 600B and the chassis 800B.

[0178] In this embodiment, the outside face of the chassis 800B has anoxide film formed on it, but instead of this, a film including resinmaterial could also be formed. As such film, there may be used, forexample, a film of a polyester resin layer and an epoxy resin layer andan acrylic resin layer stacked in this order on the chassis 800B can beused. By so doing, the temperature felt when a person touches theoutside face of the chassis 800B can be made relatively low. Also, inthe above example, by using a film having suitable coloring matter (e.g.dye) added to the uppermost acrylic resin layer, it is possible toincrease the radiation rate of the chassis 800B.

[0179] G. Seventh Embodiment:

[0180]FIG. 25 is an explanatory diagram showing conditions inside thechassis 800B in the Seventh Embodiment. The projector of this embodimentis substantially the same as the Sixth Embodiment (FIG. 22), but on themetal light source mounting section 608B, a heat pipe 440 is provided.The heat pipe 400 is fixed onto the metal light source mounting section608B by means of a metal fixing section 450.

[0181]FIG. 26 is a schematic cross sectional view when the proximity ofthe heat pipe 400 shown in FIG. 25 is cut in a plane parallel to the xzplane. The heat pipe 440 is comprised of a pipe 442, a wick 444 providedto the inside wall of the pipe 442, and a working fluid sealed insidethe pipe 442. The pipe 442 is formed of metal material of relativelyhigh thermal conductivity such as aluminum or copper. As the wick, forexample, a porous member or mesh-like member is used. It should be notedthat a groove may be formed on the inside wall of the pipe, and it ispossible to use this as the wick. As the working fluid, for example,water methanol may be used.

[0182] The heat pipe 440 is shaped such that a first end portion 440 athereof contacts the upper portion of the light source mounting section608B and a second end portion 440b thereof contacts the upper chassis810B. The first end portion 440 a functions as an evaporating portionand the second end portion 440 b functions as a condensing portion. Thatis, working fluid, in the first end portion 440a, absorbs heat from thelight source mounting section 608B and then evaporates. The vapor, inthe second end portion 440b, releases heat to the upper chassis 810B andcondenses. The working fluid condensed in the second end portion 440 bmoves by means of capillary action through the wick 444, and returns tothe first end portion 440 a.

[0183] In the way described above, the heat pipe 440 is anelectrothermal element using latent heat during evaporation and duringcondensing of working fluid. Thermal conductivity of the heat pipediffers depending on the material forming the pipe, working fluid etc.,but, for example, it has a thermal conductivity about 80 times that of acopper rod. Accordingly, by providing the heat pipe 440 on light sourcemounting section 608B, heat of the light source mounting section 608Bcan be transferred efficiently to the upper chassis 810B, and as aresult, heat of the light source mounting section 608B can beefficiently released to the outside.

[0184] The heat pipe 440 of this embodiment is arranged so as tothermally couple the base frame 600B and the chassis 800B, but it isalso possible to do this with the second end portion 440 b of the heatpipe 440 not contacting the upper chassis 810B. It can be done, forexample, with the second end portion 440 b arranged in proximity to theair inlet or outlet of second cooling fan 420B. Also, in thisembodiment, the heat pipe 440 is arranged on the light source mountingsection 608B, but instead of this, or in addition to this, it may bearranged in proximity to the polarization control elements. By so doing,the temperature rise due to heat generation of polarization controlelements can be further reduced. Generally, a projector will comprise aheat pipe.

[0185] The present invention is not restricted to the above embodimentor its modifications, but there may be many other modifications,changes, and alterations without departing from the scope or spirit ofthe main characteristics of the present invention. Some examples ofpossible modification are given below.

[0186] (1) In the First through Fifth Embodiments (FIG. 6, FIG. 15),cooling fin 610 is provided to the bottom face of the bottom portion ofbase frame 600, and the breeze from cooling fan 420, by hitting coolingfin 610, efficiently cools the base frame 600. Also, in the Sixth andSeventh Embodiments (FIG. 24), cooling fins 631-663 are provided to thebottom face of the bottom portion of the base frame 600B, and the breezefrom cooling fan 410B, by hitting the cooling fins 631-663, efficientlycools the base frame 600B. However, the cooling fans 420, 410B may beomitted in cases where installation thereof is difficult. In this caseas well, the base frame can be cooled by means of a cooling fin, so heatgenerated by polarization control elements can be efficientlytransferred to the base frame, and the temperature rise due to the heatgeneration of polarization control elements can be reduced. In the aboveembodiments, the cooling fin is provided to the bottom face (outsideface) of the bottom portion of the base frame, but could be provided tothe outside face of a side portion.

[0187] Generally, it is preferable that a cooling fin is provided to theoutside face of the base frame on which a plurality of opticalcomponents are mounted.

[0188] (2) In the above embodiments, light-transmissive membersconstituting polarization control components are formed of sapphire, butinstead of this can be formed of glass with silicon dioxide as itsprincipal component. In this case as well, heat generated bypolarization control elements can be transferred to thelight-transmissive members and the base frame, and as a result, thetemperature rise due to heat generation of polarization control elementscan be reduced. Generally, a light-transmissive member will have thermalconductivity of at least about 0.8 W/(m·K).

[0189] (3) In the First through Fourth Embodiments, optical componentsare held by separately prepared holders 710, 720, 730, 750, 790, and inthe Fifth through Seventh Embodiments, a plurality of optical componentsare held by common holders 701, 701B. In this way, in the aboveembodiments, optical components are held by holders, but the holders canbe omitted. That is, convex portions and/or concave portions can beprovided on the inside of the base frame such those as formed on theinside of the common holder 701 of FIGS. 16(A) and 16(B), and these canbe utilized to mount the optical components inside the base frame.

[0190] (4) In the above embodiments, the base frame 600, 660B is formedof metal material such as Mg alloy, Al alloy etc., but could instead beformed of resin material with metal material (metal powder) ofrelatively high thermal conductivity added. In this case as well,relatively high thermal conductivity of at least about 10 W/(m·K) can beobtained. For example, a BMC (bulk molding compound) with added aluminumoxide (Al₂O₃) can be used. BMC is a composite material of unsaturatedpolyester or other thermosetting resin reinforced with glass staplefibers. Doing so has the advantage of forming a lighter weightprojector, compared to case of forming the base frame of metal materialonly. However, when a base frame formed of metal material only (i.e., ametal base frame) is used, as in the above embodiments, thermalconductivity of the base frame can be made relatively high. This has theadvantage of further reducing temperature rise due to heat generation ofpolarization control elements.

[0191] Generally, the base frame for mounting the plurality of opticalcomponents arranged on the optical path from the illumination opticalsystem to the projection optical system will be formed of materialsincluding metal material.

[0192] (5) In the above embodiments, by means of mutual contact of abase frame and a light-transmissive member with polarization controlelements stuck to it, or, by means of interposing a member of relativelyhigh thermal conductivity contacting both a base frame and alight-transmissive member, a base frame and a light-transmissive memberare thermally coupled. In the latter case, instead of a holder, or, inaddition to a holder, a sheet of relatively high thermal conductivity(thermal conductive sheet) can be used. Specifically, by means ofcontacting a thermal conductive sheet with both a light-transmissivemember and a base frame, a light-transmissive member and a base framecan be thermally coupled. In this case, since the light-transmissivemember and the base frame are thermally coupled by means of a thermalconductive sheet, the holder can be formed of materials of thermalconductivity lower than metal materials (for example, resin materialwith the aforementioned metal material added). Also, as a thermalconductive sheet there may be a sheet made of graphite, a sheet made ofmetal etc. PGS Graphite Sheet (trademark) made by Matsushita ElectronicComponents Co., Ltd. may be used, for example, as a graphite sheet

[0193] Generally, the base frame and the light-transmissive member withpolarization control elements stuck to it will be thermally coupled.

[0194] (6) In the First through Fifth Embodiments (FIG. 6, FIG. 15), thebase frame and chassis are connected via convex portions (connectors)826, 827, 829 that attach the base frame onto the chassis. In the Sixthand Seventh Embodiments, the thermal conductive rubber 830B is arrangedbetween the base frame and chassis. Instead of thermal conductiverubber, there could be arranged the aforementioned thermal conductivesheet. Furthermore, the Seventh Embodiment, a heat pipe 440 is arrangedbetween the base frame and chassis. By so doing, heat of the base frame600B can be efficiently transferred to the chassis 800B. Generally, thebase frame and chassis will be thermally coupled.

[0195] (7) The above embodiments regard application of the presentinvention to the transmissive-type projector. The principle of thepresent invention is also applicable to reflective-type projectors. Inthe ‘transmissive-type’ projector, the electro-optical device working asthe light modulation means allows transmission of light, for example, ina transmissive-type liquid crystal panel. In the ‘reflective-type’projector, on the other hand, the electro-optical device working as thelight modulation means reflects light, as for example, in areflective-type liquid crystal panel. Application of the presentinvention to the reflective-type projector ensures the similaradvantages to those attained by application to the transmissive-typeprojector.

[0196] (8) In the above embodiments, the projector 1000 uses the liquidcrystal panels as the electro-optical devices, but may instead usemicromirror-type light modulation devices. A typical example of themicromirror-type light modulation device is the DMD (Digital MicromirrorDevice) (trade mark by Texas Instruments Incorporated). In general, anyelectro-optical device that modulates incident light in response toimage information is applicable.

[0197] (9) The above embodiments regard the projector 1000 that displayscolor images. The present invention is also applicable to projectorsthat displays monochromatic images.

INDUSTRIAL APPLICABILITY

[0198] This invention is applicable to a projector that projects anddisplays images.

What is claimed is:
 1. A projector comprising: an illumination opticalsystem; an electro-optical device for modulating light from theillumination optical system in response to image information; aprojection optical system for projecting modulated light obtained withthe electro-optical device; and a base frame, formed using materialincluding metal material, for mounting a plurality of optical componentsarranged on an optical path from the illumination optical system to theprojection optical system, wherein at least one of the plurality ofoptical components is a polarization control component comprising: apolarization control element including organic material for controllingpolarization state of light exiting from the polarization controlelement; and a light-transmissive member having a thermal conductivityof at least about 0.8 W/(m·K), to which the polarization control elementis stuck, and wherein the light-transmissive member and the base frameare thermally coupled.
 2. The projector according to claim 1 wherein thelight-transmissive member has a thermal conductivity of at least about5.0 W/(m·K).
 3. The projector according to claim 2 wherein the baseframe is made of metal.
 4. The projector according to claim 3 whereinthe polarization control component is held by a metal holder thatcontacts the light-transmissive member, and the light-transmissivemember and the base frame are thermally coupled via at least the holder.5. The projector according to claim 4 wherein the holder is fixed to thebase frame via an adhesive sheet.
 6. The projector according to claim 4wherein the holder is fixed to the base frame via adhesive.
 7. Theprojector according to claim 4 wherein the holder is fixed to the baseframe by metal welding.
 8. The projector according to claim 4 whereinthe light-transmissive member is fixed to the holder via an adhesivesheet.
 9. The projector according to claim 4 wherein thelight-transmissive member is fixed to the holder via adhesive.
 10. Theprojector according to claim 4 wherein the holder comprises: a fixingsection fixed to the base frame; and an attaching section for attachingthe light-transmissive member to the fixing section, wherein the fixingsection is fixed to the base frame via an adhesive sheet.
 11. Theprojector according to claim 4 wherein the holder comprises: a fixingsection fixed to the base frame; and an attaching section that attachingthe light-transmissive member to the fixing section, wherein the fixingsection is fixed to the base frame via adhesive.
 12. The projectoraccording to claim 4 wherein the holder comprises: a fixing sectionfixed to the base frame; and an attaching section for attaching thelight-transmissive member to the fixing section, wherein the fixingsection is fixed to the base frame by metal welding.
 13. The projectoraccording to claim 4 wherein the holder comprises: a fixing sectionfixed to the base frame; and an attaching section for attaching thelight-transmissive member to the fixing section, wherein thelight-transmissive member is stuck to at least one of the fixing sectionand the attaching section via an adhesive sheet.
 14. The projectoraccording to claim 4 wherein the holder comprises: a fixing sectionfixed to the base frame; and an attaching section for attaching thelight-transmissive member to the fixing section, wherein thelight-transmissive member is stuck to at least one of the fixing sectionand the attaching section via adhesive.
 15. The projector according toclaim 3 further comprising a metal chassis for housing all opticalcomponents arranged on the optical path from the illumination opticalsystem to the projection optical system, wherein the base frame and thechassis are thermally coupled.
 16. The projector according to claim 3wherein the illumination optical system comprises a light source device,wherein the light source device and the base frame are thermallyinsulated.
 17. The projector according to claim 16 wherein a thermalinsulating member is arranged between the light source device and thebase frame.
 18. The projector according to claim 3 further comprising acooling fin, provided on the outside face of the base frame.
 19. Theprojector according to claim 3 wherein a film for raising radiation rateis formed on the outside face of the base frame.
 20. The projectoraccording to claim 15 wherein a film for raising radiation rate isformed on the outside face of the chassis.
 21. The projector accordingto claim 3 wherein the polarization control element is a liquid crystalpanel, which functions as the electro-optical device.
 22. The projectoraccording to claim 3 wherein the polarization control element is apolarizing plate.
 23. The projector according to claim 3 wherein thepolarization control element is a retardation plate.
 24. The projectoraccording to claim 3 wherein the light-transmissive member is a lens.25. The projector according to claim 3 wherein the polarization controlcomponent further comprises a lens, the lens being provided on thelight-transmissive member of plate shape.
 26. The projector according toclaim 25 wherein the lens is formed of plastic.
 27. The projectoraccording to claim 3 wherein the light-transmissive member is a sapphiremember.
 28. The projector according to claim 3 wherein thelight-transmissive member is a rock crystal member.